fixes condition to use local prettier (#678)

lua/lsp/ts-fmt-lint.lua

@@ -10,7 +10,7 @@ M.setup = function()
         formatStdin = true
     }
 
-    if vim.fn.glob("node_modules/.bin/prettier") then
+    if vim.fn.glob("node_modules/.bin/prettier") ~= "" then
         prettier = {
             formatCommand = "./node_modules/.bin/prettier --stdin-filepath ${INPUT}",
             formatStdin = true